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Ok, I'm showing my Noob-ness again. I was in Academy and wanted to get a bottle of Hoppes oil in the little bottle with the metal tube but they didnt have any but they did have "Moly Oil" in the bottle I wanted so I bought it. What exactly is this stuff. My original plan was to dump it out and put regular gun oil in it but I figured I might as well ask and see if you guys can enlighten me.

jim\

The "moly" on the label means that the oil contains a percent or two of micron-size particles of molybdenum disulphide in suspension. MoS2 is a solid lubricant similar to graphite that has lubricating and extreme-pressure properties even in the dry state. (Extreme pressure additives are useful in certain gear oils, mainly in low-speed, high-load bearings, but are not necessary in guns.) Mostly, MoS2 allows marketers to make exaggerated claims about their product.

In gun oil, MoS2 is probably neutral in overall effect. It may slightly reduce barrel friction, but it may also act as a catylist to accelerate corrosion. It won't hurt anything to use it, but it isn't better than clear oils, either.

Diode, I'm interested in the replies here, as well. 'Cause I can't even spell molybide..., molibiden..., molybduh..., well, you know. I've thought about trying a moly product, but have never taken the plunge. One quick caveat that I'm sure is on the instructions with Hoppe's moly product is that I understand you need to do a thorough cleaning--as in a detail strip--with a non-lubricated solvent, and let the pieces completely dry, before applying the moly for the first time. Applying it over an existing layer of lubricant won't hurt anything, I don't think, but you'd be sacrificing the metal-adhering properties of the moly.

'Course, using molybdenum sulfates as a lubricant is nothing new. It's used extensively in motor sports and aviation. And the first time I remember hearing of it as a firearm lubricant was a controversy over a product called "DrySlide" (I think) during the Viet Nam War: it was a moly product that wasn't mil spec, so soldiers' families were sending to them individually. The reason the soldiers wanted it is the same reason it's a popular lubricant for motorcycle chains. On chains, it doesn't spray off or wash off in rain like regular oil, it sticks to the metal, and it has less of an attraction to dirt than oil or grease. Under the combat conditions in Nam, that sounded like a very good thing. On the chains, at least, it usually comes in a mineral spirit solvent that evaporates after application, leaving the molybdenum (sulfate or disulfide) on the metal.

The stuff looks and feels kinda like graphite. It's an extremely fine, blackish powder that's insoluble in water. I'm really not familiar with the moly products for firearms, but I would guess they come in two basic flavors: one, a "dry" application product like that for motorcycle chains; and two, in a suspension of oils or synthetic lubricants (not designed to evaporate...that's probably what the Hoppe's is). It works because the atomic attraction between molybdenum atoms and sulfur atoms is very weak, so "films" of moly atoms slide easily over the sulfates and, theoretically, surfaces of treated metals never actually come into contact. That's why it's popular in motor sports. Even if there's a hiccup in oil pressure, if the engine surfaces are moly-treated, they should continue to be slippery for a while. Oh, and of course it can also be used as a treatment for bullet surfaces to help them glide down the barrel.

My primary application would be auto-loading handguns, and I'm just too ignorant about it to understand if I want to try it or not. I don't shoot under extreme temperature, humidity, or dirty conditions (often). Too, autoloaders need some level of friction between the cartridge casing and chamber to function properly, so if I were to try a moly product, I'd probably be careful to use it in the barrel, but not the chamber. But I guess the real reason I haven't tried it is that I'm pretty set in my ways regarding cleaning. I use Cylinder & Slide's Dunk-It, which leaves a slight lubricating film, and all the rest of my stuff is geared around conventional lubricants. But if it's really a very good thing, I can be convinced to change.

Chemically, MoS2 "bonds" or, more accurately reacts, with Fe when contact pressures between two ferrous metal surfaces exceed the capacity of an oil film to provide separation, and surface asperities come into direct contact, causing microscopic hot spots which react to form iron-molybdenum sulfides. The sulfides have good boundary lubricating properties, and offer some protection against galling and wear when the oil film is breached.

Dri-Slide is just a solvent-thinned light mineral oil with MoS2 powder and ZDDP, an extreme-pressure additive used in motor oils, added. Since nothing in a gun has such high loads or contact pressures that metal-to-metal hot-spots will form, (unlike, say, a camshaft lobe in a racing engine), Dri-Slide is equivalent to a light oil when used in a gun. The reaction temperatures just aren't there in a semi-auto or revolver action for moly to have any benefit, unless an oil film is completely absent.

Moly powder is sometimes mixed with a resin and used as a coating which is sprayed and baked on surfaces. Dry powder and baked-on films do provide some lubrication where dust or high temperatures make oils undesirable. Moly, as a dry-powder spray or oil additive, does not "bond" to metals like marketers may claim. Like any other contaminant, it can adhere to a surface, but it can be easily removed with solvents.

Guns require very, very little lubrication to function well, and in dusty climates, almost dry is best. Light oils containing barium or calcium sulfonates as corrosion inhibitors, like Rem-oil or LPS #2, CLP, etc. work very well when used sparingly.

Skiprr wrote: My primary application would be auto-loading handguns, and I'm just too ignorant about it to understand if I want to try it or not. I don't shoot under extreme temperature, humidity, or dirty conditions (often). Too, autoloaders need some level of friction between the cartridge casing and chamber to function properly, so if I were to try a moly product, I'd probably be careful to use it in the barrel, but not the chamber. But I guess the real reason I haven't tried it is that I'm pretty set in my ways regarding cleaning. I use Cylinder & Slide's Dunk-It, which leaves a slight lubricating film, and all the rest of my stuff is geared around conventional lubricants. But if it's really a very good thing, I can be convinced to change.

Shucks, and all this time I thought Quaker State 30 was pretty good.
You learn something every day if you try